Can temporary mood influence people's communication strategies? According to Grice's cooperative principle, conversational utterances should ideally conform to the maxims of quantity, relevance, quality, and manner. Three experiments predicted and found that participants in a negative mood complied significantly better with Grice's maxims than did participants in a positive mood when using natural language to describe a previously observed social event. Experiments 2 and 3 further confirmed that mood influenced communication strategies, and not merely the encoding (Exp. 2) and retrieval (Exp. 3) of the relevant information. These findings are consistent with affect–cognition theories predicting that positive affect promotes a more internally focused and assimilative thinking and communication style, and negative mood promotes more externally focused and accommodative thinking, resulting in the closer observance of communication norms. The relevance of these findings for recent affect/cognition theories is considered, and the practical implications of the results for everyday conversational strategies are discussed. Copyright © 2013 John Wiley & Sons, Ltd.